Prior art which is related to this technical field can e.g. be found by the technical specification TS 32.500 current version: 8.0.0) of the 3GPP.
The following meanings for the abbreviations used in this specification apply:    3GPP: 3rd Generation Partnership Project    BS: Base Station    CDF: Cumulative Distribution Function    DM: Domain Manager    EM: Element Manager    eNB: evolved Node B (eNodeB)    FDD: Frequency Division Duplex    GPS: Global Positioning System    HO: Handover    ID: Identity    ISD: Inter Site Distance    Itf-N: Standardized interface between NM and EM or sometimes NM and NE    Itf-?: Interface between EM and NE; “?” is a placeholder, e.g. Itf-R, if NE is a RNC; or Itf-B, if NE is a NodeB    LB: Load Balancing    LTE: Long Term Evolution    NE: Network Element (e.g. a RNC, NodeB or eNodeB)    NM: Network Manager    OAM: Operation and Maintenance    RLF: Radio Link Failure    RNC: Radio Network Controller    RSRP: Received Signal Reference Power    SON: Self Organizing Networks    TA: Timing Advance    TDD: Time Division Duplex    UE: User Equipment
FIG. 1 shows a typical scenario in a cellular communication network. There are base stations 15, 16 and 17 with coverage areas 11, 12 and 13, respectively, i.e. the cells.
For example, in a LTE-based network, a base station is implemented as eNB.
A UE 10 which is in connectivity status (indicated by a broken line) with a particular base station 15 may move into an area covered by another base station 16. Since the UE 10 executes neighbor measurements (i.e. measures the signal strength of the base station 15 to which it is currently connected vs. the signal strength of neighboring base stations 16 and 17) based on a pre-defined procedure, e.g. periodically, it will detect if the signal strength of base station 16 is stronger than the signal strength of base station 15 and consequently will initiate a handover procedure in order to get into connectivity status (indicated by a solid line) with base station 16 instead of base station 15.
Apparently, the detection of signals from different base stations is only possible in areas covered by more than one base station. This is called e.g. a cell overlap area (indicated in FIG. 1 by a hatched arrow 19).
Accordingly, e.g. the transmission and/or antenna tilt of the senders of the base stations 15, 16 and 17, respectively have to be set so as to enable this.
However, inappropriate settings of the transmission power and antenna tilt can lead to large areas of cell overlap. In these areas many cells are received with similar signal strength so that UEs will suffer from high interference. Therefore, this phenomenon is also referred to as reference signal pollution.
If the cell overlap areas are too large (in FIG. 1, for coverage area/cell 11 indicated by an ellipse in broken line vs. an ellipse in solid line), excessive interference will negatively impact the system capacity and the risk of unnecessary handover between the cells with similar signal strength increases, thus yielding potential impairment on link quality, HO failures, and unnecessary signaling load.
Currently, cell overlap is entirely but exclusively considered during the network planning phase. The calculations to plan a cell coverage area and respective overlaps are based on models of the environment and the radio propagation. Though, these models have limited accuracy and require high effort.